1. Field of the Invention
The present invention relates to an apparatus for processing substrates, such as semiconductor wafers, and more specifically, to improvements in a container handling system for handing containers, such as carriers, provided in a substrate processing apparatus.
2. Description of the Related Art
A semiconductor device fabricating process uses a cleaning apparatus for cleaning semiconductor wafers, i.e., substrates, with a cleaning liquid, such as a predetermined chemical liquid or pure water, to remove contaminants, such as particles, organic contaminants and metal impurities, adhering to the surfaces of the wafers. Wet cleaning apparatus that cleans wafers by immersing the wafers in a cleaning tank containing a cleaning liquid are used prevalently.
In the known cleaning apparatus, an operator or an unmanned vehicle, such as an automatic guided vehicle (AGV), caries a plurality of carriers, i.e., containers, usually two containers, each containing twenty-five uncleaned wafers to a carrier receiving unit and places the carriers on a receiving stage installed in the carrier receiving unit. The carriers are carried by a lifter, i.e., moving means, to an unloading stage installed in the carrier receiving unit. Then, the fifty wafers are taken out of the two carriers on the unloading stage. The fifty wafers are carried to a wafer cleaning and drying unit and are subjected to a cleaning and drying process of a batch processing system. The wafers thus processed are carried to a carrier delivery unit. The wafers are loaded into empty carriers prepared on a loading stage installed in the carrier delivery unit. Then, the loaded carriers are moved to a delivery stage installed in the carrier delivery unit and are carried out of the cleaning apparatus by an operator.
A wafer counter is disposed above the unloading stage. The wafer counter counts the number of the wafers contained in each carrier and inspects the carrier for jump-slots before the wafers are taken out of the carrier. A wafer counter is disposed above the loading stage to count the wafers after the wafers have been loaded into the carriers so that any wafers may not be left in the cleaning and drying unit.
In the conventional carrier receiving unit and carrier delivery unit, the lifters and lifter driving mechanisms are disposed in spaces above the receiving stage and the delivery stage, respectively. Therefore, it is possible that the operator touches the lifter or the driving mechanism accidentally when carrying the carriers onto the receiving stage or taking out the carriers from the delivery stage and the operator is injured. Moreover, the carrier receiving unit and the carrier delivery unit are congested with the lifters and the driving mechanism and have a complicated configuration. Since the wafer counters are disposed above the unloading stage and the loading stage, respectively, it is possible that accidents occur during inspection, and the carrier receiving unit and the carrier delivery unit are further congested with the wafer counters.
Accordingly, it is a first object of the present invention to provide a container handling system in which carrier moving means are not disposed in spaces above stages on which carriers are placed.
A second object of the present invention is to provide a container handling system having inspecting means not disposed in spaces above stages and capable of efficiently inspecting the storage condition of substrates contained in containers.
A third object of the present invention is to improve container handling efficiency.
A first aspect of the present invention is a substrate processing apparatus comprising: a plurality of stages, on each of which a container for containing substrates therein is to be placed; and a first section at which the substrates are taken out from the container and/or are put into the container, wherein a first stage amongst the stages is provided at the first section; and a movable table carrying the container between the first stage and one of the stages other than the first stage, while the container being placed thereon.
A second aspect of the present invention is a method of carrying a container for containing substrates between two stages included in a substrate processing apparatus, said method comprising the steps of: (a) moving a movable table for transporting a container to a position below a surface of a first stage on which a container is placed thereon; (b) raising the movable table through a cut-away area formed in the first stage to a position above the surface of the first stage, thereby lifting up the container from the first stage by the movable table; (c) withdrawing the movable table, on which the container is placed, from a position above the first stage; (d) moving the movable table to a position above a second stage; and (e) lowering the movable table through a cut-away area formed in the second stage to a position below a surface of the second stage, thereby placing the container on the second stage.
A third aspect of the present invention is a method of handling containers for containing substrates, said method comprising the steps of: (a) delivering a plurality of containers containing substrates onto a receiving stage; (b) transferring one of the plurality of containers to an unloading stage; (c) taking out substrates from the container transferred to the unloading stage; and (d) repeating the steps (b) and (c).
A fourth aspect of the present invention is a method of handling containers for containing substrates, said method comprising the steps of: (a) putting substrates into a container on a loading stage; (b) transferring the container containing the substrates to a delivery stage after the completion of the step (a) before putting substrates into another container; (c) repeating the steps (a) and (b), thereby collecting a plurality of containers containing substrates on the delivery stage; and (d) delivering the plurality of containers collected on the delivery stage after the completion of the step (c).
A fifth aspect of the present invention is a method of handling containers for containing substrates, said method comprising the steps of: (a) delivering a plurality of containers each containing substrates onto a receiving stage; (b) transferring one of the plurality of containers to a loading/unloading stage; (c) taking out the substrates from the container transferred to the loading/unloading stage; (d) putting the substrates taken out of the container in the step (c) into the container from which the substrates were taken out in the step (c) on the loading/unloading stage; (e) transferring the container loaded with the substrates in the step (d) to a delivery stage; (f) repeating the steps (b) to (e), thereby collecting a plurality of containers loaded with substrates on the delivery stage; and (g) delivering the plurality of containers collected on the delivery stage after the completion of the step (f).